1. Field of the Invention
The present invention relates to a semiconductor power module and more particularly, to a heat releasing structure of a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), a bipolar transistor, an IGBT (Insulated Gate Bipolar Transistor), and the like which are used in power control devices.
2. Description of the Background Art
The conventional semiconductor power module is provided in such a manner that an active element (such as IGBT) and a passive element (FwDi: Free Wheel Diode) are connected through an aluminum wire, a relay terminal of a control signal is connected to the active element through the aluminum wire, an emitter electrode plate is connected to the passive element through the aluminum wire, an aluminum pattern is arranged under the active element and the passive element, a heat spreader is arranged under them with an insulating substrate interposed therebetween, and a cooling fin is also arranged under it. A collector electrode plate is connected to the aluminum pattern through the aluminum wire, and an external busbar is connected to each of the emitter electrode plate and the collector electrode plate.
Heat generated in the active element and the passive element is released by the cooling fin through the heat spreader.
Based on the above structure, Japanese Patent Application Laid-Open No. 2006-134990 discloses a structure in which a metal bar is connected to electrodes arranged on vertical both surfaces of a semiconductor element, to improve heat exchange efficiency of a heat generating part. In addition, it is described that the metal bar may be a thin-plate heat pipe.
However, in this structure, heat release is not sufficient to implement a high power, and it is difficult to implement sufficient heat releasing performance without increasing a size of a module itself.